1DFEMWATER: A one-dimensional finite element model of WATER flow through saturated-unsaturated media

Technical Report · Mon Aug 01 00:00:00 EDT 1988

DOI:https://doi.org/10.2172/7056611· OSTI ID:7056611

Yeh, G T

This report presents the development and verification of a one- dimensional finite element model of water flow through saturated- unsaturated media. 1DFEMWATER is very flexible and capable of modeling a wide range of real-world problems. The model is designed to (1) treat heterogeneous media consisting of many geologic formations; (2) consider distributed and point sources/sinks that are spatially and temporally variable; (3) accept prescribed initial conditions or obtain them from steady state simulations; (4) deal with transient heads distributed over the Dirichlet boundary; (5) handle time-dependent fluxes caused by pressure gradient on the Neumann boundary; (6) treat time-dependent total fluxes (i.e., the sum of gravitational fluxes and pressure-gradient fluxes) on the Cauchy boundary; (7) automatically determine variable boundary conditions of evaporation, infiltration, or seepage on the soil-air interface; (8) provide two options for treating the mass matrix (consistent and lumping); (9) provide three alternatives for approximating the time derivative term (Crank-Nicolson central difference, backward difference, and mid-difference); (10) give three options (exact relaxation, underrelaxation, and overrelaxation) for estimating the nonlinear matrix; (11) automatically reset the time step size when boundary conditions or source/sinks change abruptly; and (12) check mass balance over the entire region for every time step. The model is verified with analytical solutions and other numerical models for three examples.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7056611
• Report Number(s): ORNL-6423; ON: DE89001345; TRN: 88-035509
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
GROUND WATER
FLOW RATE
WATER SATURATION
MATHEMATICAL MODELS
GEOLOGIC FRACTURES
HIGH-LEVEL RADIOACTIVE WASTES
NUMBER CODES
ONE-DIMENSIONAL CALCULATIONS
SITE CHARACTERIZATION
TIME DEPENDENCE
UNDERGROUND DISPOSAL
COMPUTER CODES
GEOLOGIC STRUCTURES
HYDROGEN COMPOUNDS
MANAGEMENT
MATERIALS
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SATURATION
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER
052002* - Nuclear Fuels- Waste Disposal & Storage
053000 - Nuclear Fuels- Environmental Aspects